In a victory for the project, which has faced repeated political obstacles, a divided Surface Transportation Board ruled 2-1 that the California High-Speed Rail Authority can begin construction on its own. The initial 65-mile stretch between Fresno and Merced will be exempt from the customary requirement that railway construction first obtain prior approval from the federal board, under the ruling.

"We need not revisit the determinations on the viability and desirability of the project already made by various federal state and local government interests, all of which have a stake in the matter," the board's majority stated. "The information before us confirms that the project would be a valuable addition to the passenger rail transportation system."

"We can now focus on starting major work on the project this summer and providing thousands of jobs in the Central Valley," he said.

The decision follows an intense lobbying campaign, in which high-speed rail advocates, including California Gov. Jerry Brown, Fresno Mayor Ashley Swearengin and several labor unions urged that the board exempt the project from the prior approval requirement. Skeptics, including officials representing Kings County, the city of Bakersfield, and the Chowchilla Elementary School District, weighed in on the other side, saying continued federal scrutiny was warranted. The fight even drew in lawmakers from other states, including New Jersey, New York, Illinois and Florida.

One Surface Transportation Board member dissented from the board majority's view that no prior approvals should be necessary.

"Significant federal taxpayer dollars are at stake here, with nearly $3.5 billion in funding awarded by the Federal Railroad Administration, and those taxpayer dollars may be only the beginning," board Vice Chairman Ann D. Begeman said. "As such, I believe the public interest showing clearly merits our robust scrutiny in this case."

Begeman formerly worked as a top aide to Republican Sen. John McCain of Arizona on the Senate Commerce, Science and Transportation Committee, and had previously joined high-speed rail skeptics in urging a longer public comment period on the issue.

Thirteen Republican members of the House from California had also pressed for a longer comment period.

Earlier this year, rejecting a pitch from the California High-Speed Rail Authority, the Surface Transportation Board had concluded it had jurisdiction over the state project. Board members on Thursday reiterated their reasoning, noting the plans for "extensive interconnectivity with Amtrak, which has long provided interstate passenger rail service."

The board's majority, though, sided with the California high-speed rail planners in determining on Thursday that exempting the project from prior approval requirements would "minimize the need for federal regulation and reduce regulatory barriers."

"Overall, the public using passenger rail service will be the beneficiaries of more, and not less, passenger service as a result of the proposed project," the board's majority concluded.

The board chairman, Daniel R. Elliott III, formerly practiced as an attorney for the United Transportation Union, an Ohio-based organization that represents railroad workers. The third member, Francis P. Mulvey, is an economist who studied at the University of California at Berkeley and formerly served as a Democratic aide on the House railroad subcommittee.

The board's work on the California project included an analysis of an environmental impact statement, which the majority on Thursday called a "hard look" at the potential environmental consequences.